The JP Patent Kokai Publication 61-269936 (1986) discloses a prior art technology having pertinence to the present invention.
Referring to FIG. 9 to 11 showing a main body 1 of a conventional roll forming apparatus for metal molding laces, a plurality of rotationally driving roll stands 3, 4, . . . and a plurality of drivingless (or driven) small roll stands 2a, 2b, 2c, . . . are arrayed and drivingless small rolls 8, 9 are retained on an inclined surface and adapted to be moved vertically along double arrows. An arcuate (semi-circular) surface 6 is provided on a supporting post of a roll forming stand 2a and, which arcuate surface serves as an angle adjustment guide, the roll forming angle of the drivingless small rolls is adjustable by rotation along the direction of an arcuate arrow 6a. This adjustment is usually carried out by manual operation.